Development of technology to regulate plant growth is a key issue in promoting the supply efficiency of crop plants and horticultural plants.
Among a variety of effects manifested by the regulation of plant growth, promotion of plant growth is a typical effect. Conceivable factors that determine the growth rate of plants include temperature, light, and nutrients. From the past, in order to promote growth of a plant, attempts have been made to select appropriate temperature and light conditions in accordance with the properties of the plant of interest. In addition to such selection of temperature and light conditions, application of a fertilizer is also a well-established technique and has provided a certain effect.
However, effects yielded by application of a fertilizer are limited; i.e., an increased amount of fertilizer does not necessarily attain a growth promotion effect commensurate with such an increase. Contrary to expectations, excessive application of a fertilizer not only hampers the growth of the plant, but possibly raises the risk of pollution of soil.
In particular, in an early stage of plant growth, application of a fertilizer tends to induce nutritional disorder; therefore, application of a fertilizer is typically withheld in this stage.
Therefore, there exists demand for a compound which exhibits plant growth promoting effect and is quite different from conventional fertilizer composed of nitrogen, phosphate, potassium, etc.
There also exists demand for improvement in supply efficiency of crop plants or horticultural plants, through discovery of means for regulating, in accordance with needs, growth of plants, on the basis of various effects, including not only such promotion of plant growth, but also promoted formation of flower buds, retarded aging of plants, prevention of dormancy of plants, and mitigation of plant stresses such as drying and high temperature.
In relation to the above, the present inventors previously found that a certain class of ketol fatty acids exhibits the flower bud formation promoting activity for a broad range of plants (see, for example, Japanese Patent Application Laid-Open (kokai) No. 11-29410). Now, the inventors are in the course of clarifying that such specific ketol fatty acids are intimately involved in various life-related phenomena of plants.
Thus, a primary object of the present invention is to create, as an extension of the mentioned findings regarding the ketol fatty acids, a novel substance which meets the aforementioned subject matter, and to provide a novel plant growth regulator containing the novel substance.